Sheet registration apparatus



June 30, 1970; D. s. HOFFMAN ETAL 3,51ZQ23 SHEET REGISTRATIONAPPARATUS Filed May 24. 1968 ll Sheets-Sheet 1 INVENTORS DANIEL S. HOFFMAN HUGH L. .JONES BY a Y A TTORNEYS June 30, 1979 n. s. HOFFMAN ET AL 3,517,923

' SHEET REGISTRATION APPARATUS Filed May 24, 1968 11 Shets-Sheet 2 I INVENTORS DANIEL S. HOFFMAN BY HUGH L. JONES XQ/M Q ATTORNEYS E. S. HOFFMAN ET AL SHEET REGISTRATION APPARATUS June 30, 1910 11 Sheets-Sheet 5 Filed May 24. 1968 IN VENTORS F N ms m H W T S .1 LL .%A E 0 NW3 June 30, 1970 '0. s. HOFFMAN ET AL 3517 92235 SHEET REGISTBATIQN APPARATUS Filed May 24. 1968 ll sheets Sheet &

INVENTORS DANIEL S. HOFFMAN HUGH L. JONES A. flak.

' ATTORNEYS June 30, 197@ s, F N ET AL 3,517,923

SHEET REGISTRATION APPARATUS Filed May 24. 1968 11 Sheets-Sheet 5 v INVENTORS- DANIEL s. HOFFMAN HUGH L. JONES A TTORNEVS June 30, 1970 v 5, HOFFMAN ET AL 3,517,923

' ,SHEET REGISTRATION APPARATUS Filed May 24, 1968 11 Sheets-Sheet 6 INVENTORS Q) Jh DANIEL s. HOFFMAN I BY I HUGH L. JONES 6 4 MW. mwm

ATTORNEYS June 30, 1970 D. s. HOFFMAN ET AL 3,517,923

SHEET REGISTRATION APPARATUS Filed May 24, 1968 ll Sheets-Sheet INVENTORS DANIEL S. HOFFMAN HUGH L. JONES A T TORNEYS June 30, 1970 HOFFMAN ET AL 3,517,923

SHEET REGISTRATION APPARATUS Filed May 24, 1968 11 Sheets-Sheet a INVENTORS DANIEL S. HOFFMAN HUGH L. JONES BY /J a 440M A T TORNEYS June 30, 1970 D. s. HOFFMAN ETAL 3,517,923

SHEET REGISTRATION APPARATUS ll Sheets-Sheet 9 Filed May 24, 1968 WIN June 30, 1970 D. s. HOFFMAN ET AL SHEET REGISTRATION APPARATUS 11 Sheets-Sheet 10 Filed May 24, 1968 mm m 3 t INVENTORS DANIEL S. HOFFMAN HUGH L. JONES HY 4111 4 7 ATTORNEYS am 0km June 30, 1970 5, HOFFMAN ET AL 3,517,923

SHEET REGISTRATION APPARATUS ll Sheets-Sheet 11 Filed May 24, 1968 mxw amw

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INVENTORS DANIEL S. HOFFMAN HUGH L. JONES y fiiO/PNEKS United States Patent 3,517,923 SHEET REGISTRATION APPARATUS Daniel S. Hoffman and Hugh L. Jones, Rochester, N.Y.,

assiguors to Xerox Corporation, Rochester, N.Y., a

corporation of New York Filed May 24, 1968, Ser. No. 740,406 Int. Cl. B65h 9/06 U.S. Cl. 27153 4 Claims ABSTRACT OF THE DISCLOSURE A paper registration arrangement having two slightly spaced apart rollers and sheet edge engaging fingers arranged to coperate with the rollers. Devices are provided which will actuate the fingers out of the path of movement of a sheet and will cause the rollers to move toward each other to engage the sheet therebetween.

This invention relates to paper feed systems, and particularly, to improvements in the arrangement of registration rollers and registration fingers particularly adapted for use with automatic copiers/reproducers capable of high speed operation.

As is well known in recent years, the steadily increasing size of various industries has required an enormous increase in the amount of paper Work that must be accomplished, maintained, and made available for wide interplant circulation. In the present day commercial automatic copiers/reproduction machines, which are adapted to produce copies of between and 60 8 X 11" sheets of copy per minute, the photoreceptor device is in the form of a drum which rotates in timed unison relative to a plurality of processing stations and the usual paper feeding system is limited as to the speed of moving sheet paper material that can be conveyed to a transfer station for the machine.

As a solution for overcoming the disadvantages for high speed copying, the latest machine concept for copiers utilizes flash exposure of a document and the arrangement of a moving photo-conductor material in the form of an endless belt. However, there has been no efficient way in which to feed sheets of paper at high speed without encountering paper jams and the improper registration of the leading edge of the sheets at the same time providing fast sheet movement.

It is therefore the principal object of this invention to improve paper feeding apparatus for aiding in effecting maximum output of sheet material and to do so with a minimum of parts and space.

Another object of this invention is to align the leading edges of continuously fed sheet material and to feed the sheets after alignment in a relatively short space of time thereby minimizing time lags in high speed sheet feeding.

These and other objects of this invention are obtained by means of a pair of registration rollers arranged one above the other and a plurality of sheet edge-engaging fingers which are adapted to be moved into the path of a moving sheet to align the leading edge thereof. Actuating devices are arranged to move the two rollers, one of which is driven into engagement with the sheet to produce movement thereof, while simultaneously retracting the fingers out of the paper path.

For a better understanding of the invention as well as other objects and further features thereof, reference is had to the following detailed description of the invention to be read in conjunction with the accompanying drawings, wherein:

FIG. 1 is an exploded right-hand perspective view of a reproduction machine incorporating the present invention therein with the processing components separated to better illustrate the environment for the present invention;

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FIG. 2 is a schematic sectional view of the reproduction machine showing the various processing stations;

FIG. 3 is an isometric view of a paper handling and feeding component of the machine to which the present invention is applied;

FIG. 4 is a side elevational view of the paper handling device as viewed from the rear of the machine;

FIG. 5 is a side elevational view of the paper handling device as viewed from the front of the machine;

FIG. 6 is a plane view of the paper handling device with parts broken away;

FIG. 7 is a sectional view taken along the line 7-7 in FIG. 6;

FIG. 8 is a sectional view taken along line 8-8 in FIG. 5;

FIG. 9 is a sectional view of the paper feeding mechanism taken along line 9-9 in FIG. 5;

FIG. 10 is a sectional view with parts broken away of the paper registration rollers utilized along with the paper feeding mechanism;

FIG. 11 is an end view of the double rotary solenoid utilized to effect sheet registration and feed out;

FIG. 12 is a fragmentary enlarged view of a rotary drive device taken along the line 1212 in FIG. 11;

FIG. 13 illustrates another position of operation of the rotary device of FIG. 11;

FIG. 14 is a sectional view of a detail used with the registration rollers taken along the line 14-44 in FIG. 10;

FIG. 15 is a sectional view of another detail taken along line 1414 in FIG. 10;

FIG. 16 is a sectional view showing the registration fingers and taken along line 1616 in FIG. 10; and

FIG. 17 is a sectional view of the roller bearing support taken along line 1717 in FIG. 10.

For a general understanding of the illustrated copier/ reproduction machine, in which the invention may be incorporated, reference is had to FIGS. 1 and 2 in which the various system components for the machine are schematically illustrated. As in all electrostatic systems such as a xerographic machine of the type illustrated, a light image of a document to be reproduced is projected onto the sensitized surface of a Xerographic plate to form an electrostatic latent image thereon. Thereafter, the latent image is developed with an oppositely charged developing material to form a Xerographic powder image, corresponding to the latent image on the plate surface. The powder image is then electrostatically transferred to a support surface to which it may be fused by a fusing device whereby the powder image is caused permanently to adhere to the support surface.

In the illustrated machine, an original to be copied is placed upon a transparent support platen P fixedly arranged in an illumination assembly generally indicated by the reference numeral 10, arranged at the left end of the machine. While upon the platen, an illumination system flashes light rays upon the original thereby producing image rays corresponding to the informational areas on the original. The image rays are projected by means of an optical system for exposing the photosensitive surface of a xerographic plate in the form of a flexible photocon-' ductive belt arranged on a belt assembly generally indicated by the reference numeral.

The photoconductive belt assembly 11 is slidably mounted upon a support bracket secured to the frame of the machine and is adapted to drive a selenium belt 12 in the direction of the arrow as shown in FIG. 2 at a constant rate. During this movement of the belt, the reflected light image of an original on the platen is flashed upon the xerographic surface of the belt. The belt surface that intercepts the light rays comprises a layer of photoconductive material such as selenium on a conductive backing that is sensitized prior to exposure by means of a charging corona generator device indicated at 13.

The flash exposure of the belt surface to the light image discharges the photoconductive layer in the areas struck by light, whereby there remains on the belt a latent electrostatic image in image configuration corresponding to the light image projected from the original on the supporting platen. As the belt surface continues its movement, the electrostatic image passes through a developing station B in which there is positioned a developer assembly generally indicated by the reference numeral 14 and where the belt is maintained in a fiat condition. The developer assembly 14 comprises horizontally and vertically conveying mechanisms which carry developing material to the upper part of the belt assembly 11 whereat the material is dispensed and directed to cascade down over the upwardly moving inclined selenium belt '12 in order to provide development of the electrostatic image.

As the developing material is cascaded over the xerographic plate, toner particles in the development material are deposited on the belt surface to form powder images. As toner powder images are formed, additional toner particles are supplied to the developing material in proportion to the amount of toner deposited on the belt during xerographic processing. For this purpose, a toner dispenser generally indicated by reference numeral 15 is used to accurately meter toner to the developer material in the developer assembly -14.

The developed electrostatic image is transported by the belt to a transfer station C whereat a sheet of copy paper is moved at a speed approximately in synchronism with the moving belt in order to accomplish transfer of the developed image. There is provided at this station a sheet transport mechanism generally indicated at 16 adapted to transport sheets of paper from a paper handling mechanism generally indicated by the reference numeral 1 8 to the developed image on the belt at the station C.

After the sheet is stripped from the belt 12, it is conveyed into a fuser assembly generally indicated by the reference numeral 21 wherein the developed and transferred xerographic powder image on the sheet material is permanently afiixed thereto. After fusing, the finished copy is discharged from the apparatus at a suitable point for collection externally of the apparatus.

Suitable drive means may be arranged to drive the selenium belt 12 in conjunction with timed flash exposure of an original to be copied, to effect conveying and cascade of toner material, to separate, and feed sheets of paper and to transport the same across the transfer station C and to convey the sheet of paper through the fuser assembly in timed sequence to produce copies of the original.

It is believed that the foregoing description is suflicient for the purpose of this application to show the general operation of an electrostatic copier using an illumination system constructed in accordance with the invention. For further details concerning the specific construction of the electrostatic copier, reference is made to copending application Ser. No. 731,934, filed concurrently herewith in the name of Hewes et al.

The sheet feeding mechanism 18 illustrated in FIGS. 3-9 is positioned for the seriatim feeding of cut sheet transfer material into contact with the xerographic belt 12 so that developed powder images on the surface of the belt may be transferred to the transfer material. The mechanism includes a tray for holding a supply of cut sheet transfer material, separator rollers and devices for separating a single sheet of transfer material from the top of the stack of transfer material on the tray, feed rollers for feeding a single sheet into the transport system '16 in order to bring the sheet into impression contact with the belt 12 and means for coordinating the operation of the separator rollers and feed rollers to thereby feed a single sheet of transfer material into contact with the belt 12 at proper registration of the powder image on the belt onto the transfer material. A tray level control device is also provided for raising the tray as sheets of transfer material are fed from the top of the material supply.

Referring now specifically to the drawings, the apparatus for feeding sheets of transfer material to the transport system 16 in timed relation to the appearance of a developed image on the belt 12 includes a paper tray 400 slidably positionable from the side of the machine between frame plates 401, 402 and arranged to hold a stack S of various widths of sheet material such as paper.

The paper tray 400 includes a paper stack supporting base comprising two sections: a stationary base section 403, and a movable base plate 404, both plates being coplanar and including fiat relatively wide fingers 405 (see FIG. 6-) which intermesh when both plates are joined to support a stack of paper. The fingers 405 support the stack when the rearwardly extending movable base plate 404 is pulled rearwardly to the position shown in dotted lines in FIG. 7 and indicated by the numeral 406. The base plate may be placed in this position when loading the paper tray with long (legal size) paper which requires the machine to run in a long pitch mode.

The stationary plate 403 is held against movement within its plane by means of box-like structur 407 having one edge 408 welded to an intermediate plate 409 which in turn is spot welded to the bottom surface of the stationary plate 403. The sides of the intermediate plate 409, which extends in a plane parallel to and below the combined plane for the plate 403, 404 are formed into downwardly projecting tapered side panels 411 which are held against forward or rearward movement by a slide mechanism to be described hereinafter. The intermediate plate 409 is formed with a slot 412 arranged centrally between the side panels 411 and extending for nearly the entire length of the plate 409. Through this slot extends a pair of screws 413 secured to the bottom surface of the central finger 405 of the movable base plate 404. These screws serve to support a ribbon 414 positioned parallel to and below the plate 404 and is formed with a depending portion 415 which is adapted to engage an actuator 416 of a switch SW when the movable plate 404 is pulled rearwardly. The switch SW may be connected as an interlock circuit to effect change in machine pitch resulting from the use of longer sheets of transfer material. In loading the paper tray with longer sheets, the plate 404 is extended not only to accommodate longer sheets but also to condition the machine for the long pitch mode.

Each of the side panels 411 is adapted to be driven vertically in order to cause raising and lowering of the paper tray during paper feed operation. To this end, the base plate 401 has secured thereto a channel member 42.0 having its open side extending inwardly and arranged in a vertical position. Similarly the base plate 402 is provided with a channel member 421 secured thereon to face the channel 420. The channel member 420 is adapted to receive a pair of guide rollers 422 mounted in spaced relation upon a vertically extending plate 423 secured in a vertical arrangement upon one of the side panels 411. In like manner, the channel 421 serves to guide vertically a pair of vertically spaced rollers 424 mounted upon a plate 425 secured to the other side panel 411. With this arrangement, the paper tray is free to move vertically and is held against horizontal movement by the confinement of the side panels 411 to the fixed channels 420, 421.

In order to produce control and automatic movement of the paper tray vertically, the forward edges of each of the plates 423, 425 is provided with a gear rack 426, 427 respectively. A train of three vertically aligned gears are adapted to drive each of the gear racks in order to impart vertical motion of the paper tray. As shown in FIG. 7,

r the gear rack 427 is in direct mesh with an upper gear wheel 428 mounted for rotation upon a stud shaft 430 secured to the frame plate 402.. Mounted below the gear 428 upon a stud shaft 431 is an intermediate gear 432. Below the intermediate gear 432, is a third lower gear 433 secured to a drive shaft 434 having one end secured in a bearing to the frame plate 402, and its other .end bearing mounted for rotation on the frame plate 401.

This completes the three gear train for the side of the paper feeder frame which supports the gear rack. 527. On the other side of the paper frame is a second gear train comprising gears 435, 436 and 437 arranged on stud shafts 43-8, 439 respectively for the gears 435 and 436 and the drive shaft 434 to which the lower-most gear 437 is secured. It will be apparent that the shaft 430 and 438 are in actual alignment as are the shafts 431 and 439. It will also be apparent that upon rotation of the lowermost gears, 433 and 437, motion will be imparted to each of the respective upper gears which in turn produce corresponding movement of the respective gear racks 426, 427.

In order to produce rotation of the lowermost gears,

the outer extremity of the drive shaft 434 on that side d of the sheet feed mechanism having the base plate 401, has secured thereto a drive gear 440 which is in mesh with a worm gear 441 formed on a shaft 442 mounted for rotation between flanges of a bracket 443 which also supports a paper elevation motor M-2 having its shaft connected to the shaft 442 for imparting rotation thereto. Preferably the motor M-2 is adapted to produce a low r.p.m. rotation which when coupled with the worm gear 441 and drive gear 440 impart relatively slow motion to the paper tray.

Centering of the stack S of paper relative to the optical centerline of the copier/ duplicator machine in order to insure proper registration and feeding of individual sheets of paper from the top of the stack is accomplished by a pair of vertically extending guide members 445, 446 arranged at the forward corners of the stack when in position for separation operation. The guide member 445 is supported in an upright position by means of a horizontally extending guide pin 447 suitably secured to the frame plate 401 and extending through a boss 448 formed in the guide member 445. Similarly, the member 446 is supported in a vertical position by a guide pin 450 secured to the frame plate 402 and slidably received in a boss 451 formed in the upright. The guide members 445 and 446 are also formed at the lower ends with bosses 452, 453 for supporting the guide members 445, 446 and to permit movement of these guide members toward and away from each other.

As shown in FIGS. 7 and 9, the guide member 445 is formed with a guide edge 454 that extends vertically along the length of the guide member and adapted to engage the leading edge of the stack of paper at one corner thereof. Engaging the side edges of the stack S along the same corner is a guiding surface 455 also formed along the length of the member 454. The guide member 446 is similarly formed with a front guide edge 456 and a side guide edge 457 for guiding the leading and side edges of the stack of paper at that corner. The side edges 455 and 457 are adapted to be moved toward and away from each other and relative to the center line of the paper tray 400 in order to center the stack S relative to the optical axis of the xerographic machine as the axis will manifest itself during the image transfer step.

In order to drive the side edges 455, 457 toward and away from each other, the paper feeder 18 is provided with a manually operable centering drive system comprising a pair of links 460, 461 each having an end connected to one of the bosses 452, 453 and the other end connected to a block 462 mounted for rotation upon a shaft 463. The points of connection of the links 460, 461 with the block 462 are offset relative to the axis of rotation for the block in order to cause movement of the bosses 452, 453 upon rotation of the block 462 in either direction. Rotation of the shaft 463 is accomplished by a knob 464 secured at the outer end of the shaft 463 at the rear of the paper handling mechanism 18. A lock knob 465 secured to the extremity of the shaft 463 serves to move the knob 464 axially relatively to the shaft and against a non-rotatable block 466 mounted on a spacer plate 469 and held axially thereto by a suitable shoulder 467 formed on the shaft. Rotation of the knob 465 will lock the knob 464 against rotation in order to prevent inadvertent driving movement being imparted to the guide members 445, 446. It Will be apparent that upon rotation of the knob 464, the block 462 will be rotated for driving the links 460, 461 in either direction in order to impart corresponding movement of the bosses 452, 453 respectively. During a paper loading operation, the knob 464 is rotated to space the members 445, 446 apart to accommodate various widths of transfer material on the tray 400 and to permit the easy loading of additional sheets upon the tray. After the tray has been supplied with sheets the knob 464 is rotated to drive the guide members toward each other in unison thereby aligning the stack relative to the optical center line of the xerographic machine and in proper position for paper feeding.

The driving action produced by the knob 464 and the shaft 463 in order to separate the members 445, 446 is against the bias of a spring 468 held in tension by being connected at its ends to each of the guide members and normally biasing them toward one another. Preferably, the spring is of such a strength that with the knob 464 left unsecured the guide members will be normally forced inwardly against the adjacent side edges of the stack of papers thereby enhancing good side-toside alignment.

The coacting side guide edges 455, 457 coacting with guide follower elements 470 secured on the outwardly extending ends of a pair of rods 471, 472 held in axial alignment and being slidably mounted within blocks 473, 474 respectively, secured below and in spaced relation to the stationary plate 403 of the paper tray support the corners of the stack of transfer material. A rod 475 is slidably retained in the opposing ends of the rods 471, 472 and has a spring 476 encircling it in order to maintain the rods 471, 472 outwardly to force the follower elements 470 against the guide members 445, 446. The guide elements 470 fill the corner gaps and support paper of all widths.

Generally, the upper ends of the guide edges 454, 456 are held at a point slightly below the top sheet of the stack S. As individual sheets of paper are fed from the stack, each is adapted to slide or to be driven over the top ends of the members. Means are provided for separating only the top sheet from the stack during a paper fed operation. In order to insure separation of the topmost sheet only from the stack, there is provided at opposite corners of the stack, separating devices which apply a light restraining force on the forward corners of the topmost sheet and the leading edge of the paper stack. Each of the separating devices comprise a vertically movable plunger 476, 477 freely movable in a vertical passageway 478 formed in each of the forward portions of the guide members 445, 446. Each of the plungers has a snubber 480, 481 secured thereto at a plane slightly above the upper ends of the plungers and to be movable therewith.

The weight of each of the plungers 476, 477 is imposed on the upper forward corners of the paper stack. Normally the weight on each corner is such that the plungers will follow the level of the stack downwardly as the stack level is lowered by continuous feeding of paper. Their weights also provide a restraining force which will assist in the feeding of a single sheet of paper when the stack is acted upon by separator rollers to be described hereinafter. It is preferred that the limits of downward movement for the plungers 474, 476 are short in order to limit the downward movement of the corresponding snubbers. This is to limit the lowering of the snubbers when the level of the stack is lowered prior to a tray loading procedure and to guarantee that the snubber are atop the corner of a freshly loaded stack without manual manipulation thereof. As it is raised assuming proper centering by the guide members 445, 446 the adjacent corners of the stack will engage the snubbers and carry them upwardly until the top of the stack is at its proper predetermined position for feeding of the top sheet.

To feed sheets of paper one at a time from the stack S and into the narrow slot formed between two closely spaced guide chutes 482, 483 arranged just forward of the top few sheets of the stack S, there is provided a paper separating means comprising a first pair of intermittently driven roller 485 mounted for rotation adjacent the side edges of the stack and a second pair of driven rollers 486 mounted inwardly of the rollers 485. All of the rollers are engageable with the top of the paper stack. Each of the outboard rollers 485 is mounted for rotation on and by a driven shaft 487 associated with each of the rollers by means of a one way clutch 488 which permits each roller 485 to rotate freely in that direction that the topmost sheet moves when it is pulled out from the stack at a greater rate than the roller is capable of moving the sheet.

The inboard rollers 486 are mounted for rotation upon a drive sleeve 490 which is drivingly connected to each roller by means of a one way roller clutch 491 similar to the clutch 488. The shafts 487 are mounted each within an end of the drive sleeve 490 which also contains within its interior a coil spring 492 which serves to force the two shafts 487 outwardly for positioning the outboard rollers 485 to a predetermined position relative to the edge of the stack. This outward movement is limited by suitable buttons 493 which engage the edge guide 455, 457. As the guide members 445 and 446 are moved outwardly the shafts 487 will follow the same in order to insure that the rollers 485 maintain their set relation to the edges of the stack regardless of stack width.

Rotation is imparted to each of the shafts 487 by a pin 494 connected between each shaft and the end of the drive slee ve 490. The sleeve 490 at each end is formed with a slot into which each pin is adapted to be inserted for connecting the shaft and for permitting limited axial movement of each outer roller 485.

Driving rotation is imparted to the drive sleeve 490 by way of a timing pulley 495 secured axially of and at the center of the sleeve and held between the flanges of a channel support arm 496 which supports the sleeve 490 and the rollers 485, 486. The channel arm 496 is formed in two parts: a forward part 497 the end of which supports the sleeve 490 as previously stated and a supporting section 498 which conforms with the shape and direction of the portion 497. These sections are connected in endto-end relation by means of an opposing slot 500 formed in the portion 498 and coacting tongue 501 on the section 497 loosely insertable in the slot 500 to permit disconnection of the parts 497, 498. The loose connection between the slot 500 and tongue 501 also permits limited rotation of the portion 497 about its longitudinal axis in order to allow all four rollers to contact the material surface regardless of stack deformation due to humidity.

The purpose of this limited rocking movement will be described hereinafter.

The portions 497, 498 are detachably held One to another by means of an adjusting screw 502 positioned within the channel shape of the arm 496 and which is threadedly received at one end in a tapped portion 503 formed in the section 498 and at its other end that is received in a boss 504 formed in the portion 497. A suitable retaining ring is employed relative to the boss 504 for permitting rotary action of the screw 502, but preventing axial motion relative to the boss. Screw 502 need only be rotated until it becomes disengaged with either the block 503 or the boss 504 thereby permitting re moval of the portion 497. The screw 502 serves as adjustment means between the portions 497 and 498 to control tension on the timing belt utilized to rotate the rollers 485, 486.

The support arm 496 is secured between the frame plates 401, 402 by means of a sleeve 505 which is mounted at one end through a knurled thimble 506 which is rotatably adjustable and supported upon a support sleeve 507 secured by suitable screws to the frame plate 401. Normally the arm 4% is under the influence of gravity in a direction to maintain the two pairs of rollers 485, 486 into engagement with the topmost sheets of the paper stack. However, additional force must be added in order to increase the force of the rollers upon the stack. This is accomplished by means of a torsion spring 508 having one end secured to the thimble 506 and its other end connected to a retaining plate 509 through which the sleeve 505 extends and is secured. The spring 508 may be adjusted in tension between its two supporting structures in such a manner as to impart rotation to the support sleeve 505 in addition to that rotation produced by gravity for more reliable feeding of heavier weight transfer material. When the stack is removed, the retaining plate 509 also serves to limit the downward movement or rotation of the arm 496 and prevent the undue stress on the structural parts. The retaining plate 509 also serves to actuate the up elevator switch SW3 and the down elevator switch SW4 in a manner to be described hereinafter.

Held within the support sleeve 505 and extending across almost the distance between the plates 401, 402 is a drive sleeve 510 mounted for rotation at one end by a bearing 511 having its outer race secured to the inner recess of the support sleeve 507 and, a clutch mechanism 512 supported by suitable screws upon the frame plate 402. Axially rotatable within the drive sleeve 510 is a drive shaft 513 supported at one end in a bearing 514- mounted within the support sleeve 507 and at the other end extending beyond the frame late 402 and terminating in a drive pulley 515 for a suitable drive system. The clutch is adapted, when energized, to operatively connect the drive shaft 513 with the driven sleeve 510 in order to produce rotation of a timing pulley 516 positioned between the flanges of the arm 496 and which is associated with a timing belt 517 also wrapped around the timing pulley 495 in order to impart rotation thereto. During operation when the clutch 512 is energized, rotative motion is imparted to the pulley 516 which correspondingly imparts rotation to the timing pulley 495 for rotating the inboard paper feed rollers 486 and consequently the outboard rollers 485.

In operation, as the topmost sheet is frictionally advanced by the rollers 485, 486 the leading edge corners of the sheet engage the snubbers 480, 481 which are formed so as to present a continuation of the vertical front guide edges 454, 456 and hence a vertical barrier to the passage of sheets, but one limited to the outer extremes of the leading edge of the forward moving topmost sheet. As the rollers 485, 486 apply a forward force to the topmost sheet, the two forward corners of the sheet thus restricted by the snubbers, create a lag in the forward movement of the corners as the sheet is continually advanced. This lag will produce slight inward sliding movement of the corners of the sheet of paper with consequent buckling of the sheet. This buckling action of the topmost sheet insures its separation from the underlying sheets in the stack.

During feeding of the topmost sheet into the space between the guide bafiles 482, 483, both pairs of feed rollers 485, 486 are positively driven to aifect this movement. As the sheet advances, its leading edge moves into the gate of the slightly separated registration rollers 520, 521 which eventually engage the sheet and pulls the same their remaining distance in order to clear the stack S. This second movement of the sheet is slightly faster than the initial driving action produced by the feed rollers 485, 486 and thereby results in the feed rollers rotated individually and freely in view of the individual one-way clutches associated with each of the rollers. Actually at this point, when the registration rollers 520, 521 take over control of the feeding of the sheet, energization of the clutch 512 is terminated thereby stopping the positive drive action by the drive sleeve 490. In the event the topmost sheet becomes slightly askew as it is advanced across the remaining portion of the paper stack, perpetuation of this unwanted skew condition is prevented in view of' the fact that the feed rollers 485 and 486 will stop individually and sequentially as the topmost sheet trailing edge is pulled from under them. Without individual oneway clutches, the next sheet in the stack will skew as each successive roller drops off the trailing edge of the previous sheet being skewed. Since these rollers would be secured to a common shaft, none can stop turning until all have cleared the trailing edge. Rollers still on a skewed top sheet will continue to drive those rollers that have cleared the trailing edge, thereby urging that portion of the next sheet forward, perpetuating the skew.

The paper tray 400 is limited in its downward movement by means of a limit switch SW-7 mounted upon the frame plate 401 and electrically connected to the paper elevation motor M-2 through a suitable logic circuit for de-energizing M2 upon activation of the switch when the tray reaches a predetermined low position. This is accomplished by means of a projection 522 secured to the plate 425 and which actuates the switch SW-7 at the predetermined low point. Another switch SW-8 mounted on the frame plate 401 controls the upper limit of travel of the paper tray 400 by means of a projection 523 mounted on the plate 425. In the event the tray 400 attains a predetermined high point, the switch SW-S is actuated through a suitable logic circuit in order to terminate energization of the paper elevation motor M-2.

In the sheet registration mechanism illustrated in FIGS. 10 and 14-17, the registration rollers 520, 521 are adapted to cooperate with a pair of registering fingers interposed in the path of movement of a sheet being fed by the separator rollers 485, 486 in order to align the leading edge of each sheet to a precise position before the sheet is permitted to continue on to the paper transport mechanism 16 whereat the developed electrostatic image on the belt 12 will be transferred. As shown in FIG. 10, the top registration roll 520 comprises a central metallic core 525 having a plurality of soft rubber layers 526 therearound adapted to engage frictionally a sheet of paper. The roller 520 is mounted at one end on a stub shaft 527 (see FIG. supported in a bearing housing 528 held by a clamp 530 to the shaft and, at its other end on a stub shaft 531 supported in a bearing housing 532 held thereto by a clamp 533.

At the left end of the registration roller 520 as viewed in FIG. 10, a sprocket 534 is secured to the stub shaft 531. The bearing housings 528 and 532 are eccentric in nature so as to provide adjustment to the pinch between the upper register roller 520 and the lower roller 521. The end of the registration roller 520 is also supported by levers 535, 536 (see FIGS. 4 and 5) pivotally mounted at their ends by fixed stub shafts 537 secured on the frame plates 401, 402 respectively, in axial alignment. The stub shaft 537 that is fixed to the plate 402 also has secured thereto a sprocket 538 which is arranged in driving connection with the sprocket 534 by a drive chain 540 for driving the registration rollers to be described hereinafter. A suitable idler sprocket 541 is also mounted on the lever 536 and operatively associated with the chain 540 to permit tightening of the chain 540 or removal thereof from the operating sprockets.

The top edge of the frame plate 401 is formed with a generally vertically extending slot 542 into which the stub shaft 527 for the upper roller 520 is adapted to be placed when this roller is in operating position. Similarly, the shaft 531 the other end'of the roller is adapted to be positioned within the open ended slot 543 formed in the upper edge of the frame plate 402. The provision of the slots permits the pivoting movement of the driven roller 520 away from the lower idler roller 521 and out of the path of movement of the paper and, in fact, away from the cooperating structure therefor to permit maintenance and paper jam clearing.

Located immediately below the top registration roller 520 and parallel therewith, the lower roller 521 comprises a plurality of free wheeling, short rollers 544 all of which are rotatably mounted with ball bearings upon a common sleeve 545 which is rotatably mounted on a shaft 546 by means of a roller bearing 547 provided at each end thereof. The shaft 546 is mounted at one end to the frame plate 401 by suitable bearings and at the other end by a bearing 548 secured in a solenoid mount 549. At this end, the shaft 546 terminates in a straight slot 550 into which projects a tongue 551 formed on the end of a movable actuator 553 for a double-acting rotary solenoid 554, the details of which will be described hereinafter. The solenoid 554 comprises an up solenoid SOL-1 and a down solenoid SOL-2 and is adapted to impart nonaxial rotary motion to the drive shaft 546 in either direction for approximately 45 upon energization of each of the solenoid coils associated with the solenoids SOL-1 and SOL-2.

Mounted upon the sleeve 545 between any two of the free wheeling rollers 544 are registration fingers 555 which are secured by suitable set screws upon the sleeve 545 to be moved therewith or held stationary when the sleeve is held against rotation.

As shown in FIG. 16, the periphery of the roller 520 is slightly spaced from the periphery of the rollers 544. This spacing is greater than the thickness of a sheet of paper and permits the sheet to enter within the nip between the rollers and, against the fingers 555 and to maintain this position until a feed cycle is activated. At this time in the cycle, paper is still being driven by the feed rollers 485, 486. This action is opposed by the fingers 555 in the paper path causing the paper to buckle momentarily, squaring the front edge. With the forward edge of a sheet of paper against the fingers 555, the upper roller 520 is continuously driven but being spaced slightly from the top surface of the sheet of paper it is incapable of driving the sheet beyond the fingers 555. In order to permit the proper alignment of the forward edge of the sheet of paper against the registration fingers 555 and then to accomplish forward feeding movement to the sheet by means of the rollers 521, 520, the registration system is provided with a control mechanism which controls the movement of the upper roller 520 downwardly into engagement with the sheet of paper located therebelow in order to drive the same at the same time as the retracting movement of the fingers 555 in order to eliminate the impeding action by these fingers against the forward edge of the sheet.

This control mechanism includes a first link member 556 (see FIG. 17) arranged to encircle both shafts 531, 546 for the rollers 520; 521 respectively adjacent the frame plate 402 and, a second link member 557 (see FIG. 15) arranged to encircle both shafts for the upper and lower registration rollers adjacent the frame plate 401. These link members more or less hold the two rollers in superimposed close relationship. Movement of the upper registration roller 520 toward the lower roller a slight increment is accomplished during energization of the solenoid SOL-2. Upon this energization, the actuator 553 is rotated an angular distance of 45 which action imparts similar rotation to the drive shaft 546. As shown in FIG. 17, a crank 558 secured to the shaft 546 of the lower roller 521 and having a cam pin 559 arranged for movement in a cooperating arcuate internal cam 560 formed in the lower end of the link 556 is adapted to force the shaft 531 toward the shaft 546. As previously stated, the levers 535 and 536 permit limited movement of the upper roller 520 toward and away from the lower roller 521. As the crank 558 is rotated clockwise as viewed in FIG. 17, the cam pin 559, as it moves from the right hand end of the cam 564) to approximately the center point thereof, will drive the link member 556 slightly downwardly carrying therewith the roller 520 toward the roller 521.

In order to maintain the fixed position of the shaft 546 for the lower roller, the link 556 is formed with a vertical extending slot 561 through which the shaft 546 extends. This provides a lost motion connection between the link 556 and the shaft 546 during the slight upper and lower movement of this link. Continuing movement of the cam pin 559 from the approximate center point of the cam 560 to the left hand end of the cam, a total angular distance equal to 45 produced by the continued rotation of the solenoid SOL-2 armature 553, the dis tance between the axes of the shafts 531 and 546 remains the same. This movement of the cam pin 559 can be considered dwell time for the operation of the motion producing mechanism to effect engagement of the rollers 520, 521 in order to permit the remaining rotation of the shaft 546 to perform another function, that of rotating the registration fingers 555 out of engagement with the leading edge of a sheet of paper positioned in the paper guides 482, 483.

The mechanism to control movement of the fingers 555 is illustrated in two sequences of operation in FIGS. 14 and 15 and is effected by actuation of the link member 557. The link member 557 is identical with the link member 556 and is formed with a vertical straight slot 562 through which the shaft 546 extends for lost motion when the link member 557 is moved and, an internal cam 563 through which a control cam pin 564 projects. The curvature and angular relationship and distance of the earn 563 relative to the axis of the shaft 546 is the same as the cam 560. Consequently during rotation of the shaft 546 in a clockwise direction, as viewed in FIG. 14, the positioning and movement of the pin 564 is the same as the pin 559.

Secured to the shaft 546 adjacent the link member 557 is a sector gear 565 to which the cam pin 564 is attached. Meshing with the gear 564 is a second sector gear 566 mounted for rotation on a pivot pin 567 secured to the frame plate 401. The pivot pin 567 also supports for rotation thereon a cam member 568 (see FIG. 15) secured to the sector gear 566 and made adjustable therewith by means of a set screw 569 threadedly received in the member 568 and engagable with the sector 566 to permit angular adjustment of one with the other. It will be apparent upon rotation of the shaft 546, the sector 565 will be rotated and the cam in 564 will be moved in the cam 563 thereby driving the link member 557 downwardly. This motion of the link member 557 is simultaneous and equal to the motion of the downward link 556 in order to impart the smooth uniform motion of the roller 520 downwardly.

As shown in FIG. 15, the cam member 568 is formed with an angled internal cam which is formed so as to have a first cam portion 570 with a center of curvature approximately coincident with the axis of the pivot pin 567 and a second cam portion 571 which merges with one end of the angled cams but extends radially toward the pivot pin axis. The angled cam is adapted to control movement of a rotatable actuating element 572 rotatably mounted on the shaft 546 adjacent the sector gear 565 and secured to one end of the sleeve 545. This is accomplished by means of a control pin 573 secured to one end of the actuating element 572 and retained within the cam portions 570, 571 to be movable therein. Upon rotation of the link 568 from the position shown in FIG. 15 wherein the pin 573 is in the arcuate cam portion 570 of the angled cam, no rotation is imparted to the actuating member 572 that is, the register fingers 555 will not be rotated. This result occurs because the control pin 57 3 merely slides in an arcuate cam as the cam member 568 pivots about its axis. This initial rotation of the member 568 is produced by the initial energization of the solenoid armature SOL2 which action also produces the short movement of the control pin 559 for the first portion of its movement in the cam 560 as previously described. The resultant action merely keeps the upper roller 520 against the lower roller 521 and the register fingers in dwell.

When the pin 573 reaches the end of the cam 570' at the apex of the cam angle, continued rotation of the link member will actuate the pin 573 in the same direction therewith to produce clockwise rotation of the actuating element 572 as viewed in FIG. 15 in order to produce slight rotation of the sleeve 545 along its axis. Since the fingers 555 are secured to the sleeve 545, this last motion of the rotation of the link members 557 causes movement of the fingers away from the leading edge of the sheet of paper between the rollers 520, 521. This rotation of the fingers will be clockwise as viewed in FIG. 16. The set screw 569 is utilized to orientate the member 568 relative to the sector gear 566 in order to insure proper rotation of the actuating member 572. at a time when the rollers 520, 521 are in engagement. When this occurs, the upper rollers 520 engages the short rollers 544 of the lower rollers to impart rotation thereto for driving the sheet therebetween at the same time that the fingers 555 are moving in the same direction as the leading edge of the sheet but in additional downwardly motion in order to become clear of this edge.

From the foregoing, the paper sheet feeding mechanism 18 is adapted to feed continuously individual sheets of paper to the sheet registration device in the form of the rollers 520, 521 and the fingers 555 located in the path of movement of the paper. The sheet registration device arrests and aligns each individual sheet of material and then in timed relation to the movement of the xerographic belt 12 advances the sheet material into contact with the belt in registration with a previously formed xerographic powder image on the belt.

As previously stated, the double-acting rotary solenoid 554 comprises a pair of pan-cake solenoids SOL-1 and SOL-2, and is arranged to produce rotation of the shaft 546 in either direction without the usual incidental movement in the axial direction. In accomplishing this function, the up solenoid SOL-1 has its armature 574 in the form of a fiat disc and arranged to be rotated in one direction when the solenoid is energized and, the down solenoid SOL2 has its armature 575 also in the form of a flat disc arranged to be rotated in the opposite direction when this solenoid is energized.

The disc armatures are arranged in parallel planes and have their axes in alignment. Each is formed with an axial opening through which a rotary element 576 extends and is secured to the armatures to be movable therewith as a unit. The element 576 slidably receives the actuator 553 and is provided with internal teeth that mesh with the splined exterior surface of the actuator to which is connected the tongue 551 and groove 550 as a driving connection to the shaft 546 for the lower registration roller 521. As each of the armatures 574 and 575 is moved by its respective energized solenoid coil, it moves the element axially along the actuator and moves the other armature away therewith.

Upon energization of either of the coils for the sole noids, the respective armature will be driven in rotational movement. This rotary motion is produced by the cooperative action of a plurality of balls 577 rotatably held within a pair of coacting inclined depressions 578 formed one on the outer surfaces of each armature and the other in cover plates 579 which may surround the solenoids as a casing therefor. The depressions 578 are disposed so that their longitudinal axes and therefore, the

inclined surfaces are circular having a radius of curvature on the axes for the armatures. Each of the cover plates 579 and armature associated therewith are held one parallel to the other and close enough so that the balls are retained within the inclined depressions in the armatures and their coacting inclined depression 578 in the cover plates.

In operation, when the solenoid SOL-2 is energized and the other SOL1 de-energized, the armature 575 is attracted to the coil for SOL-2. This causes the element 576 to slide to the right, as viewed in FIG. without producing axial movement of the actuator 553. Movement of the element 576 causes the other armature 574 to be driven toward the adjacent cover plate 579, this is, from the position shown in FIG. 12 to that shown in FIG. 13. The normal magnetic action of the coil for the solenoid SOL-2 would want to force the armature to the right as viewed in FIG. 10. Since the balls 577 prevent axial motion directly, the magnetic force will cause the balls to move along the inclined planes of the depressions 578 on the plate 579. Because of the locking action between the balls and the leading edges of the inclined planes of the depressions formed in the armature 574, the same will be caused to rotate. The armature 574 will rotate in an amount determined by the length of the depressions 578 and the distance the armature is allowed to move axially. For purposes of actuating the upper registration roller 520 into a paper feeding position and to reposition the fingers 555, the amount of angular rotation desirable is approximately 45 In the event the up solenoid SOL-1 is energized, the armature 575 will be rotated in the opposite manner as the armature 574. Regardless of which of the solenoids are energized, both armatures with the element 576, secured therebetween will move as a unit and will slide relative to the actuator 553. However, the actuatorwill be rotated, the direction being determined by which of the solenoids being energized. With the up solenoid SOL-1 energized, the roller 520 will be held in its uppermost position and the fingers 555 in a sheet engaging condition.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration, and that the invention may be modified and embodied in various other forms without departing from the scope of the appended claims.

What is claimed is:

1. In a sheet advancing apparatus of the type wherein sheets are forwarded in a path of movement between two superimposed feed rollers having shafts mounted in parallel, apparatus for aligning sheets as they are fed to the rollers and feeding each sheet therethrough, including means connected to the shafts of each of said rollers and adapted to effect radial movement of at least one of the rollers toward the other whereby the rollers move toward engagement,

means for rotating at least one of said rollers continuously whereby the rotating movement will impart movement to a sheet in engagement with the rollers and rotative movement to the other roller,

a plurality of sheet register fingers positioned for movement into interference relationship with the path of movement of a sheet, and

actuator devices associated with said roller connecting means and said register fingers and adapted when actuated for substantially simultaneously positioning said fingers out of the path of a moving sheet and moving the rollers into driving engagement of the sheet thereby advancing the same therebetween.

2. The apparatus of claim 1 including a control device connected to the shaft of the other of said rollers and adapted when activated to one condition of operation to actuate said actuator devices whereby said fingers are positioned out of the path of a moving sheet as said rollers are moved toward each other.

3. The apparatus of claim 2 wherein said control device when activated in another condition of operation is adapted to actuate said actuator devices whereby said rollers are moved away from each other and the fingers are positioned into the path of movement of a sheet.

4. The apparatus of claim 1 including power means connected to the shaft of the other of said rollers and adapted to rotate the shaft in either direction, said actuator devices including elements operably connected to the shaft of said other roller and adapted to effect said positioning of the fingers out of the path of a moving sheet and movement of the rollers toward each other when said shaft is rotated in one direction and the reverse of the operation when the shaft is rotated in the other direction.

References Cited UNITED STATES PATENTS 1/ 1963 Kelchner 271-53 9/1967 Petrovsky 27153 US. Cl. X.R. 271- 

